It can be obtained as the trajectory of the second intersection
point between a line and a circle turning around one of their points, either
in the same direction and the circle four times as fast as the line, either
in opposite directions and the circle turning twice as fast as the line.It can also be obtained as the trajectory of the second
intersection point between two identical circles turning around one of
their points, in opposite direction, one of them turning twice as fast
as the other.

Therefore, it is a hypotrochoid
(base circle with radius ,
rolling circle with radius ,
distance from the point to the rolling circle = ),